In general, many techniques have been used over the years to measure the cutting forces of a blade cutting different materials. For example, the wool felt cutter test measures the force on a blade as the blade cuts through wool felt. This method has worked satisfactorily over previous years for measuring the force on the blade as the blade cuts through the wool felt. However, the wool felt cutter test is only able to differentiate between blades when the differences in the cutting force exerted on the blades have relatively high measurable differences.
Another drawback with the wool felt cutter test is that it measures the force on the blade. The blade is held in a stationary position with a sensor attached to the blade. The wool felt is then moved across the blade edge to be cut. The sensor detects the force exerted on the blade as the blade edge cuts the wool felt.
In the wool felt cutter test, it is not known how many fibers are actually present in the wool felt. Furthermore, when the test is conducted it is not known how many fibers are actually cut by the blade and how far from the base the fibers have been cut.
Furthermore, in the wool felt cutter, blades have to remain static and dynamic cutting action like a sawing motion cannot be studied.
W02011109369 describes a method for measuring the cutting force of a single fiber when cut by a blade. However, in order to accurately determine the cutting force representative of a shaving application, there is still a need to simulate the anchorage of the hair within the hair follicle in the skin, so that the effect on the cutting force can be determined.
There is also a need to prevent the fiber being pulled out of the fiber mount during the cutting process of the blade.
Moreover, there is also a need for a method and apparatus which enables rapid multiple cutting force measurements to be taken from a single fiber.
There is also a need to provide a method for measuring the cutting forces with a relatively high degree of sensitivity in order to determine the differences in the cutting forces between different blades.
There is a need to provide a method for measuring the cutting forces on different types of fibers.
There is a need to provide a method for measuring the cutting forces on hairs having different physiology and/or different chemical or mechanical treatment prior to cutting.
There is a need to provide a method for measuring the cutting force on hairs when the blades oscillate in specific direction, e.g. create a sawing, chopping or scraping movement, or with blades that are heated or electrically charged.